Simulation Dynamics

Case study · Resource management

Nuclear weapons rehab: 25 years of resource needs

Government manufacturing: SDI built a database-driven model for Y-12 to test resource and processing scenarios for component rehab over 25 years.

Built with Supply Chain Builder
Nuclear weapons rehab: 25 years of resource needs model view

Summary

Background

The National Nuclear Security Administration (NNSA) Y-12 National Security Complex is a manufacturing facility operated by BWXT Y-12. Y-12's missions include ensuring the US' nuclear weapons deterrent, storing nuclear materials, and fueling US naval reactors. In order to understand the impacts of these diverse missions on its numerous functional divisions, Y-12 has relied on simulation modeling.

Model Purpose

SDI developed the Integrated Resource Planning Model (IRPM), a general purpose simulation model which allows Y-12 wide latitude in describing specific production scenarios through entries in database tables. The two Winter Simulation Conference papers below, written by the Y-12 team, describe the IRPM and the database-driven architecture behind it.

Equipment rehab flow: units needing rehab are disassembled (unusable parts discarded), parts are rehabbed, then units are assembled with new parts as needed and shipped.

Key model inputs

Nuclear weapons requiring rehab are forecasted as an input to the model. Components are sorted into discards, those requiring rehab, and those that can be reused as-is. Finished units are assembled from reusable, rehab and new components. Key inputs are:

  • Component processing rates
  • Production resource availability
  • Percentage of components requiring rehab

Key Experiment Factors

  • Resource scenarios
  • Processing requirements scenarios

System Performance Measures

  • On time delivery
  • Resource Utilization
  • Inventory levels

Key Model Issues

Equipment rehab flow with four key issues: push flow into disassembly, excess inventories of reusable parts, acquisition of new parts, and pull flow into assembly.

Model Database

IRPM system diagram: official databases (project plans, HR data, shop floor data) feed an MS Access database behind a GUI, which sends model input to and gets results from the supply chain model (order, assign, fill, route).
Database-driven models like this one encode decades of production knowledge — failure modes, repair distributions, process rates, shift schedules. This structured knowledge is now viewable and shareable through the Cloud DB platform, free from proprietary tool dependencies.

Strategic Assessment

  • Long Term resource management
    This model is designed to assess resource requirements over a 25-year horizon with a wide range of varying supply and demand scenarios.

Papers

A Supply Chain Paradigm to Model Business Processes at the Y-12 National Security Complex; Kress, R; Dixon, J.; Insalaco, T.; Rinehart, R., 2007 Winter Simulation Conference.

Database-Intensive Process Simulation at the Y-12 National Security Complex; Kress, R.; Bills, K.; Dixon, J.; Rinehart, R., BWXT Y-12, 2006 Winter Simulation Conference. Documents the database-driven architecture behind this model: built in SDI Supply Chain Builder, run entirely from database tables, with no items in the model at all.

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